While validating that device serial0 was really a serial port
See Obtaining and Building GRUB, for more information.
GRUB is designed to address the complexity of booting a personal computer; both the program and this manual are tightly bound to that computer platform, although porting to other platforms may be addressed in the future.
Only kernels loaded at 1 megabyte or above are presently supported.
Any attempt to load below that boundary will simply result in immediate failure and an error message reporting the problem.
In addition to the requirements above, GRUB has the following features (note that the Multiboot Specification doesn’t require all the features that GRUB supports): Support a human-readable text configuration file with preset boot commands.
You can also load another configuration file dynamically and embed a preset configuration file in a GRUB image file.
Search for while validating that device serial0 was really a serial port:
When booting with GRUB, you can use either a command-line interface (see Command-line interface), or a menu interface (see Menu interface).